&middot a small indefinite quantity (especially of a liquid); "he had a drop too much to drink"; "a drop of each sample was analyzed"; "there is not a drop of pity in that man"; "years afterward, they would pay the blood-money, driblet by driblet"--Kipling

&middot a sudden sharp decrease in some quantity; "a drop of 57 points on the Dow Jones index"; "there was a drop in pressure in the pulmonary artery"; "a dip in prices"; "when that became known the price of their stock went into free fall"